underside
🇺🇸
/ˈʌndərsaɪd/
🇬🇧
/ˈʌndəsaɪd/
The part of something that is on the bottom or lower surface.
She looked at the underside of the leaf to see the tiny insects.
彼女は小さな昆虫を見るために葉の裏側を見た。